[100.03] Dynamical Evolution of Galaxy Disks in CDM models

A long lasting problem in our understanding of the evolution of disk
galaxies is the question of how stellar disks respond to encounters with
the numerous dark matter sub-halos predicted by the Cold Dark Matter
cosmology. We address this issue through a set of high resolution
numerical simulations that include a realistic distribution of satellites
(with masses and orbital parameters as predicted by CDM models), orbiting
around a typical stellar disk, like the Milky Way's. This is the first
numerical study to account for the interactions of multiple satellites
with a disk within the full cosmological context. The primary
conclusion of our study is that the disk is able to survive in this
violent environment for several Gyrs, thus weakening the
argument calling for a revision of the CDM paradigm. The
only visible adjustments made by the disk to the incoming satellites are
through the (angular momentum conserving) tilting, and through changes in
the kinematical properties of the stars: minor vertical disk heating,
flaring and warping. Changes in the disk structure are driven mainly by a
few massive satellites rather than by the cumulative effect of many minor
mergers.